1. Field of the Invention
The present invention relates to an apparatus and a method for preparing a sliced specimen used in physical and chemical sample analysis, microscopic observation of a biotic sample, and the like.
2. Description of the Related Art
Conventionally, a microtome is generally known as an apparatus for preparing a sliced specimen used in physical and chemical sample analysis, microscopic observation of a biotic sample, and the like. The microtome is an apparatus for slicing a surface layer portion of a specimen block by using a manually-operated cutter, the specimen block being obtained by embedding a specimen such as a biotic sample in an embedding substance such as paraffin.
A thin slice sliced by the microtome is extremely thinly sliced, and therefore is in a curling state. In order to stretch this thin slice, the thin slice is put in a bath filled with a liquid for stretch, such as water or hot water, by using a brush or paper, for example. When the thin slice is stretched by the liquid in the bath, the thin slice in the bath is scooped by using the brush and paper, and is applied to a slide by using an adhesive liquid (such as water). Alternatively, the slide is put in the bath, the thin slice in the liquid is directly scooped and is applied to the slide.
The thin slice disposed on the slide tightly adheres to the slide by further stretching wrinkles and the like by heating the slide. The thin slice adhering to the slide becomes tightly fixed to the slide with evaporation of the adhesive liquid, and is used as a sliced specimen for tissue observation.
The preparation work of the sliced specimen by using the microtome as described above is conventionally performed manually by an operator, and requires much time and labor. Several days are usually required for processing several dozens of specimen blocks even by an operator skilled in using the microtome, and also this is a repetition of the same operation. Therefore, the operator has to bear an excessive burden physically and mentally. In addition, a plurality of slices are put in the bath, thus involving a problem of contamination between specimens through the liquid.
Further, although a thickness required for the sliced specimen is different depending on the specimen, an extremely thin slice in a range, e.g., from 3 μm to 10 μm is required, and high uniformity is also required. Meanwhile, in the conventional method using the microtome, height position aligning of the specimen blocks and position (height) adjustment of cutters are visually performed by the operator. Therefore, there is a variation in accuracy (thickness and uniformity) of the sliced specimens depending on the operator, and even in a case of the same operator, a variation in the accuracy of the sliced specimens occurs due to a fatigue degree of the operator. Therefore, an apparatus capable of reducing the burden of the operator and reducing deterioration of the accuracy of the sliced specimen is required.
Japanese Laid-Open Patent Publication No. 2004-28910) discloses an apparatus for sticking a sliced specimen that sticks a specimen onto the surface of a slide, wherein the sliced specimen is obtained by slicing a specimen block in which a sample is embedded in paraffin and the like by a cutter, this sliced specimen is carried by a carrier tape, thereafter the carrier tape is run to send the sliced specimen to a front face of the slide, and next the carrier tape is made in tight contact with the surface of the slide, thereby sticking the specimen to the surface of the slide.
In this apparatus, the specimen block is transferred with a surface layer portion of the specimen block contacting a cutting blade of the cutter, and the surface layer portion of the specimen block is sliced, to thereby prepare the sliced specimen. In addition, this apparatus is operated in such a way that by controlling the running of the carrier tape, the slice carried by the carrier tape is moved to the front face of the slide coated with an adhesive liquid, thereafter the thin slice is stuck onto the slide by putting the carrier tape closer to the surface of the slide, and the slide is heated to stretch the wrinkles of the slice, which is then transferred to the outside of the apparatus.
Incidentally, in the aforementioned apparatus, the sample embedded in this specimen block is sliced along a transfer direction of the specimen block, and therefore face preparation for a top face of the specimen block is important. Namely, when the specimen block is inclined at a predetermined angle, the thickness of the sliced specimen is thereby influenced, thus making it impossible to prepare the sliced specimen with a uniform thickness.
Further, Japanese Patent No. 3656005 discloses a method of preparing a specimen by adjusting an inclination angle of the specimen when using a microtome. In this document, the surface of the specimen block formed with a flat surface in advance is pressed against a reference surface, and a face preparation for the specimen block is performed.
Generally, when the surface layer portion of a specimen block is sliced by a cutter, paraffin and the like is stuck to the blade edge of the cutter, thereby deteriorating the accuracy of slicing of the sliced specimen to be prepared next. Particularly, when the specimen block is continuously sliced by using the same area of the blade edge of the cutter, a cutting quality of this area of the cutter is gradually lowered, thus significantly deteriorating the accuracy of the sliced specimen.
In order to solve the above-described problem, Japanese Laid-Open Patent Publication No. 11-153521 discloses a microtome by which a cutter is moved to automatically change the contacting area, so that the contacting area where the blade edge of the cutter firstly contacts the surface layer portion of a specimen block does not concentrate on the same area, when the surface layer portion of the specimen block is continuously sliced. According to the apparatus of Japanese Laid-Open Patent Publication No. 11-153521, by moving the cutter so as to automatically and suitably change the contacting area, it is possible to reduce the burden of the operator, such as an replacing work of the cutter or a changing work of an attachment position of the cutter, and also it is possible to reduce the deterioration of the accuracy of the sliced specimen by constantly maintaining a good cutting quality of the cutter.
However, in the aforementioned apparatus of Japanese Laid-Open Patent Publication No. 11-153521, a shift occurs in some cases in height position of the blade edge of the cutter that contacts the specimen block before and after the movement of the cutter, due to wear by friction between the cutter and a holder holding the cutter, caused by repeated movement of the cutter. Also, a difference occurs in height position of the blade edge of the cutter that contacts the specimen block, due to individual variability of the cutter and attachment adjustment of the cutter to the holder (for example, a fastening adjustment of a screw when the cutter is screw-fixed to the holder).
Therefore, in the aforementioned apparatus of Japanese Laid-Open Patent Publication No. 11-153521, when the shift occurs during automatically and continuously slicing the sliced specimen, there occurs such a failure that missing in slicing operation of the cutter occurs, or the thickness of the sliced specimen becomes smaller or larger than the thickness required for the sliced specimen, or the blade sticks into the specimen block to damage the specimen block, thus deteriorating the accuracy of the sliced specimen. In order to solve such a defect, for example, the operator must always monitor the operation of the apparatus for preparing the sliced specimen, and when the accuracy of the sliced specimen is deteriorated or the shift occurs in the height position of the blade edge of the cutter that contacts the specimen block, the operator must perform the work such as stopping the apparatus and adjusting the height position of the cutter or the specimen block, and the operator's burden is further increased.
Further, the apparatus disclosed in Japanese Laid-Open Patent Publication No. 2004-28910 is adapted to transfer a thin slice to the outside of the apparatus every time one piece of the thin slice is stuck to the slide. Accordingly, when a large number of thinly sliced specimens are prepared, the number of slides are also increased, thus involving a problem that a drying space is increased and a cost is accordingly increased.
In addition, quantity of work of a staining work, being the next step, is large amount, thus involving a problem of inviting a wasteful amount of staining reagent and deterioration in efficiency of experimental evaluation.
Accordingly, in order to solve the above-described issues, a technical object of the present invention is to provide an apparatus and a method for preparing the sliced specimen, for automatically sticking the thin slice to the slide.